1 /*
2 * Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #ifndef SHARE_MEMORY_METASPACE_VIRTUALSPACENODE_HPP_
26 #define SHARE_MEMORY_METASPACE_VIRTUALSPACENODE_HPP_
27
28 #include "memory/virtualspace.hpp"
29 #include "memory/memRegion.hpp"
30 #include "utilities/debug.hpp"
31 #include "utilities/globalDefinitions.hpp"
32
33 class outputStream;
34
35 namespace metaspace {
36 namespace internals {
37
38 class Metachunk;
39 class ChunkManager;
40 class OccupancyMap;
41
42 // A VirtualSpaceList node.
43 class VirtualSpaceNode : public CHeapObj<mtClass> {
44 friend class VirtualSpaceList;
45
46 // Link to next VirtualSpaceNode
47 VirtualSpaceNode* _next;
48
49 // Whether this node is contained in class or metaspace.
50 const bool _is_class;
51
52 // total in the VirtualSpace
53 MemRegion _reserved;
54 ReservedSpace _rs;
55 VirtualSpace _virtual_space;
56 MetaWord* _top;
57 // count of chunks contained in this VirtualSpace
58 uintx _container_count;
59
60 OccupancyMap* _occupancy_map;
61
62 // Convenience functions to access the _virtual_space
63 char* low() const { return virtual_space()->low(); }
64 char* high() const { return virtual_space()->high(); }
65
66 // The first Metachunk will be allocated at the bottom of the
67 // VirtualSpace
68 Metachunk* first_chunk() { return (Metachunk*) bottom(); }
69
70 // Committed but unused space in the virtual space
71 size_t free_words_in_vs() const;
72
73 // True if this node belongs to class metaspace.
74 bool is_class() const { return _is_class; }
75
76 // Helper function for take_from_committed: allocate padding chunks
77 // until top is at the given address.
78 void allocate_padding_chunks_until_top_is_at(MetaWord* target_top);
79
80 public:
81
82 VirtualSpaceNode(bool is_class, size_t byte_size);
83 VirtualSpaceNode(bool is_class, ReservedSpace rs) :
84 _is_class(is_class), _top(NULL), _next(NULL), _rs(rs), _container_count(0), _occupancy_map(NULL) {}
85 ~VirtualSpaceNode();
86
87 // Convenience functions for logical bottom and end
88 MetaWord* bottom() const { return (MetaWord*) _virtual_space.low(); }
89 MetaWord* end() const { return (MetaWord*) _virtual_space.high(); }
90
91 const OccupancyMap* occupancy_map() const { return _occupancy_map; }
92 OccupancyMap* occupancy_map() { return _occupancy_map; }
93
94 bool contains(const void* ptr) { return ptr >= low() && ptr < high(); }
95
96 size_t reserved_words() const { return _virtual_space.reserved_size() / BytesPerWord; }
97 size_t committed_words() const { return _virtual_space.actual_committed_size() / BytesPerWord; }
98
99 bool is_pre_committed() const { return _virtual_space.special(); }
100
101 // address of next available space in _virtual_space;
102 // Accessors
103 VirtualSpaceNode* next() { return _next; }
104 void set_next(VirtualSpaceNode* v) { _next = v; }
105
106 void set_reserved(MemRegion const v) { _reserved = v; }
107 void set_top(MetaWord* v) { _top = v; }
108
109 // Accessors
110 MemRegion* reserved() { return &_reserved; }
111 VirtualSpace* virtual_space() const { return (VirtualSpace*) &_virtual_space; }
112
113 // Returns true if "word_size" is available in the VirtualSpace
114 bool is_available(size_t word_size) { return word_size <= pointer_delta(end(), _top, sizeof(MetaWord)); }
115
116 MetaWord* top() const { return _top; }
117 void inc_top(size_t word_size) { _top += word_size; }
118
119 uintx container_count() { return _container_count; }
120 void inc_container_count();
121 void dec_container_count();
122 #ifdef ASSERT
123 uintx container_count_slow();
124 void verify_container_count();
125 #endif
126
127 // used and capacity in this single entry in the list
128 size_t used_words_in_vs() const;
129 size_t capacity_words_in_vs() const;
130
131 bool initialize();
132
133 // get space from the virtual space
134 Metachunk* take_from_committed(size_t chunk_word_size);
135
136 // Allocate a chunk from the virtual space and return it.
137 Metachunk* get_chunk_vs(size_t chunk_word_size);
138
139 // Expands/shrinks the committed space in a virtual space. Delegates
140 // to Virtualspace
141 bool expand_by(size_t min_words, size_t preferred_words);
142
143 // In preparation for deleting this node, remove all the chunks
144 // in the node from any freelist.
145 void purge(ChunkManager* chunk_manager);
146
147 // If an allocation doesn't fit in the current node a new node is created.
148 // Allocate chunks out of the remaining committed space in this node
149 // to avoid wasting that memory.
150 // This always adds up because all the chunk sizes are multiples of
151 // the smallest chunk size.
152 void retire(ChunkManager* chunk_manager);
153
154 void print_on(outputStream* st) const { print_on(st, K); }
155 void print_on(outputStream* st, size_t scale) const;
156 void print_map(outputStream* st, bool is_class) const;
157
158 // Debug support
159 DEBUG_ONLY(void mangle();)
160 // Verify counters, all chunks in this list node and the occupancy map.
161 DEBUG_ONLY(void verify();)
162 // Verify that all free chunks in this node are ideally merged
163 // (there not should be multiple small chunks where a large chunk could exist.)
164 DEBUG_ONLY(void verify_free_chunks_are_ideally_merged();)
165
166 };
167
168 } // namespace metaspace
169 } // namespace internals
170
171 #endif /* SHARE_MEMORY_METASPACE_VIRTUALSPACENODE_HPP_ */